Eagle Electronics 640c manual Transducer location High speed Trolling speed

For example, some (but not all) manufacturers use a layer of fiberglass, then a core of balsa wood, finishing with an outer layer of fiberglass. Re- moving the inner layer of fiberglass and the balsa wood core exposes the outer layer of fiberglass. The transducer can then be epoxied directly to the outer layer of fiberglass. After the epoxy cures for 24 hours, fill the remaining space with polyester resin. When the job is finished, the hull is watertight and structurally sound. Remember, the sonar signal must pass through solid fiberglass. Any air bubbles in the fiberglass or the ep- oxy will reduce or eliminate the sonar signals.

Testing Determines Best Location

Ideally, the shoot-thru transducer should be installed as close to the transom as possible, close to the centerline. This will give you the best performance during high speed maneuvers.

Transducer location	Transducer location
(high speed)	(trolling speed)

Shoot-thru-hull transducer locations for high speed or trolling speed operation.

To choose the proper location for shoot-thru-hull mounting, follow these testing procedures: (You may need a helper to complete these steps.)

1.Anchor the boat in about 30 feet of water. Add a little water to the sump of the boat. Plug the transducer into the sonar unit, turn it on, then hold the transducer over the side of the boat in the water. Adjust the sen- sitivity and range controls until a second bottom echo is seen on the dis-

play. You'll need to turn off Auto Sensitivity, Auto Depth Range and ASP. Try a range setting that is two to three times the water depth. The

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